Gland plate

ABSTRACT

A gland plate includes a rigid, disk-shaped element that includes at least one radially extending wall having a thickness of from about 0.1 to 4 mm.

FIELD OF THE INVENTION

This invention relates to gland plates and particularly, but notexclusively, to gland plates which are fitted to or form part ofmechanical seals which are used in connection with rotating devices orequipment in many different types of industries.

BACKGROUND OF THE INVENTION

A mechanical seal comprises a “floating” component which is mounted tobe axially movable around the rotary shaft of, for example, a pump, anda “static” component which is axially fixed, typically being secured toa housing. The floating component has a flat annular end face, i.e. itsseal face, directed towards a complementary seal face of the staticcomponent. The floating component is urged towards the static componentto close the seal faces together to form a sliding face seal, usually bymeans of one or more spring members. In use, one of the floating andstatic components rotates; this component is therefore referred to asthe rotary component. The other of the floating and static componentsdoes not rotate and is referred to as the stationary component.

Those seals whose floating component is rotary are described as rotaryseals. If the floating component is stationary, the seal is referred toas a stationary seal.

If the sliding seal between the rotary and stationary components areassembled and pre-set prior to despatch from the mechanical sealmanufacturing premises, the industry terminology for this is “cartridgeseal”. If the rotary and stationary components are despatchedindividually (unassembled) from the mechanical seal manufacturingpremises, the industry terminology for this is “component seal”.

Mechanical seals are used in all types of industries to seal a varietyof different process media and operating conditions. The generalindustry term which defines the area adjacent to the process media is“inboard”. The industry term which defines the area adjacent to theatmospheric side is “outboard”.

With the exception of the mechanical seal faces, the most costly item ofa cartridge mechanical seal is the gland plate. The raw material for agland plate is typically either cast metal or a solid metal bar.Alternative materials such as plastic are also occasionally used.Subsequent machining operations on the gland plate raw material arerequired in order to accurately fit the mating components.

For most types of mechanical seals, typically, one seal gland isemployed for each size of seal in both single and double seal formats.With over 30 standard seal sizes, in any given product range and atleast two gland formats, a company's gland plate inventory costs can beconsiderable. Furthermore gland production costs are high due to thenumber of manufacturing operations required to process a given gland.

There is a need for a seal gland which is of relatively low costincluding the use of material which, after the original manufacturingoperation, requires no subsequent machining such as turning, milling ordrilling.

STATEMENTS OF THE INVENTION

According to the present invention there is provided a gland platecomprising a rigid disk-shaped element including at least one radiallyextending wall having a thickness of from 0.1 to 4 mm.

Preferably the thickness of the wall is from 1 to 2 mm and morepreferably is about 1.5 mm.

Preferably set element comprises two axially spaced, radial extendingwalls. More preferably said element further includes inner and outercircumferential walls extending between said radially extending walls.

Preferably the element is a hollow structure. Alternatively the elementmay be filled with a suitable material such as concrete, plastics orwater.

Preferably said wall or walls of the elements are made of metal and morepreferably said wall or walls are formed by a pressing operation.

The gland plate according to the present invention may include a firstpart providing a first radially extending wall and a second partproviding a second radial extending wall, said first radial extendingwall being axially spaced from said second radial extending wall.

Preferably said first and second parts together provide inner and outercircumferential walls.

Preferably the gland plate is provided with one or more through holes,more preferably formed by a pressing or punching operation.

Preferably the material displaced when the or each of said holes isbeing formed provides a strengthening support around said hole.

Preferably a gland placed in accordance with the present invention is inthe form of a hollow structure having first and second radiallyextending walls as well as means for feeding fluid through said glandplate.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are as follows:

FIG. 1 shows a cross sectional view of a conventional prior art singlecartridge mechanical seal;

FIG. 2 shows a cross sectional view of a single cartridge mechanicalseal of the invention and FIG. 2 b shows an alternate setting cliparrangement;

FIG. 3 corresponds to FIG. 2 and shows a cross sectional view of thegland plate assembly of the invention;

FIG. 4 corresponds to FIGS. 2 and 3 and shows an isometric of the twopressed components which, when assembled, make the gland plate assemblyof the invention;

FIG. 5 corresponds to FIG. 4 and shows an exploded isometric view of thetwo pressed components which, when assembled, make the gland plateassembly of the invention;

FIG. 6 shows an alternative single cartridge seal of the invention,showing by way of example only, a different gland plate assembly;

FIG. 7 corresponds to FIG. 6 and/or FIG. 4 and shows a quarter isometriccutaway of the gland plate assembly of the invention;

FIG. 8 illustrates an alternative design of the invention, showing analternative shaft-sealing device;

FIG. 9 illustrates an alternative design of the invention, showing asingle component seal arrangement;

FIG. 10 illustrates an alternative design of the invention, showing adouble cartridge seal arrangement;

FIG. 11 illustrates an alternative design of the invention, showing adouble component seal arrangement; and

FIG. 12 illustrates an alternative design of the invention, showing agland plate assembly and packing arrangement.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described, by way of examples only, withreference to the accompanying drawings.

The conventional prior art single cartridge mechanical seal depicted inFIG. 1 includes a gland plate 1 which requires a considerable number ofmachining operations and machine set-ups to allow mating components tobe assembled and placed.

The total cost of the gland plate 1 is the sum of the machining costsand the costs of the raw material. As illustrated, the raw material ofthe gland plate 1 in FIG. 1 is a casting. If the gland plate ismanufactured from a solid material, the raw material cost would belower. However the machining costs are typically considerably more.

FIG. 2 shows a single cartridge mechanical seal 4 of the invention. Therotary and axially floating seal face 11 is spring biased towards astatic stationary seal face 12. The rotary seal face 11 is allowed toslide on the static seal face 12. The interface between the rotary sealface 11 and stationary seal face 12 forms sealing area 13. This sealingarea 13 is the primary seal that prevents the process media 14 fromescaping from the process chamber 15.

In addition to the sliding seal face 13, the process media 14 is sealedby a sleeve elastomer 16 in contact with the shaft 17 and sleeve 18.This has been termed the first secondary sealing area.

The second secondary sealing area is formed between stationary seal face12 and stationary gland plate assembly 21 using elastomeric member 22.

The third secondary sealing area is formed between the rotary seal face11 and the sleeve 18 using elastomeric member 24.

The fourth secondary sealing area is formed between the gland plateassembly 21 and the process chamber 15 using gasket 26.

The four secondary sealing areas and the primary sliding sealinginterface prevent the process media 14 from escaping from the processchamber 15.

The static seal face 12 is prevented from rotating by radial squeezebetween the elastomeric member 22 and the gland plate assembly 21. Analternative anti-rotation device could be incorporated into the designif so desired.

The sleeve 18 is axially terminated adjacent to the clamp ring 23 whichcontains at least one screw 28 for securing the seal assembly 25 to theshaft 17. Screw 28 provides rotational drive from shaft 17 to the rotarycomponents in the seal assembly 26. Rotary seal face holder assembly 26consists of at least one holder 27. This holder, preferably metallic inconstruction, transmits the axial spring 28 a force to the seal face 11.

Preferably, although not essential, at least one setting clip 29 is usedto position the axial and/or radial distance between the rotating clampring 23 and gland plate assembly 21. The latter is provided with anintegral annular hook 29 a for engagement with the setting clip 29.

The setting clip 29 could be either removable using clip screw 5 or, asshown in FIG. 2 b, setting clip 6 could be a sacrificial wearing memberof seal assembly 25.

Sacrificial clip 6 may be of continuous circular construction or splitinto segments. Since sacrificial clip 6 is a potentially wearingcomponent, it is preferably made from a suitable material such asplastic or brass. Furthermore, if clip 6 has a continuous circularsection, it should be sufficiently flexible to allow engagement into thegland clip recess 7.

FIG. 3 corresponds to FIG. 2 and shows a partial cross section throughthe gland plate assembly 21.

The gland plate assembly 21 is typically constructed from more than onepart. The front plate 30 aligns on at least one feature with the rearplate 31. Preferably, alignment is made on either the outer radialportion 32 of the front plate 30 or the inner radial portion 33 of thefront plate 30. As shown in FIG. 3 it is preferable if said locationfeatures are both the inner 33 and outer 32 radial portions of the frontgland plate 30 since this provides strength to the gland plate assembly21. This also provides a surface where an adhesive could be applied.

The location features on the front gland plate 30 could be of any shapeor size, and/or positioned in the rear gland plate 31, or positioned onany combination of both front 30 and rear 31 gland plates.

Since both front 30 and rear 31 gland plates are manufactured frompressed material steel, preferably a non-corrosive steel material suchas stainless steel, the gland plate assembly 21 manufacturing costs areextremely low.

The experienced reader will note that pressed sheet steel, of say 1.0 mm0.040″ to 1.5 mm 0.060″ thickness, can be extremely strong when designedin a manner where the physical shape of the cross section, including thebends in the material, create a rigid structure.

From FIG. 3, the gland plate assembly 21 has preferably at least onebolt slot 34 which allows the gland plate assembly 21 to be fixed to theprocess chamber 35 mounting face, using an appropriate screw 36.

FIG. 4 corresponds to FIG. 3, and shows an isometric view of the glandplate assembly 21. The gland plate assembly 21 has preferably four-boltslots 34 equal spaced which allows it to be fixed to the processchamber. The gland plate assembly 21 is held together both axially androtationally by at least one crimp indentation 37 in the outer radialsurface of the gland plate assembly 21. It is preferred that said glandplate assembly 21 is further held together by either a suitableadhesive, chemical bond and/or permanent physical operation such aswelding.

From FIG. 3, should the design of the invention be constructed from morethan one piece of sheet metal, particularly around the bolt slot area34, the slots 38 and 39 in both front 30 and back 31 plates should alignwith each other.

FIG. 5 illustrates an isometric view of the front 30 and back 31 plates,which make up the respective gland plate assembly 21 shown in FIG. 4.

During the gland plate 30 and 31 manufacturing process, the bolt slots39 and 38, are typically formed in the sheet material by a pressing orpunching operation. During said operation, the sheet material isdisplaced 40. The displaced material 40 surrounding the circumference ofthe slot 38 and 39 is advantageous as this provides strength to thisarea of the gland plates 30 and 31. This is important since at least onescrew and the resulting clamping force from the screw is transmittedinto this area of the gland plate 30 and 30.

It is deemed to be of further benefit, when at least two gland plates,front 30 and back 31 are utilised in the gland plate assembly 21 as thecombined strength is a multiple of the two components.

From FIG. 3, it is advantageous, although not essential, to allow theaxial end 41 of the displaced slots 38 and 39 in the both front 30 andback 31 plates to butt against each other.

If both axial ends 41 of the displaced slots butt against each other,the resulting compressive force from screw 36 has to buckle thedisplaced material surrounding either slot 38 and 39, particularly ifthe gland back face is flush against the process chamber face 35. Thisbutted displaced slot design is therefore very strong and able towithstand compressive loads from screws or bolts acting through theslots 38 and 39.

From FIG. 3, it is of further advantage if the front gland plate 130axially locates against the back gland plate 31 at its outwardly radialand axial position 41 and/or its inwardly radial and axial position 42.Therefore as compressive force is applied from the screw 36, the outerand inner most radial portions of the front gland plate 30 gain axialsupport from the back gland plate 31.

FIG. 6 shows another single cartridge seal design of the invention. Thegland plate assembly 50 is extended axially away from the gasket 51bolting face thereby allowing the stationary seal face 52 andcorresponding rotary seal face 53 to be positioned further outboard tothat of FIG. 2.

This offers certain advantages, for example, if a rotary seal face head53 is radially too large for the rotating equipment seal chamber bore54, the design shown in FIG. 6 allows the rotating seal face head 53 tobe positioned in the gland plate assembly 50. This prevents rotatingequipment modifications.

Alternatively, if there is insufficient axial room due to an obstruction56 inside the rotating equipment, the rotating seal face 53 and sleeve55 can be positioned axially away from the obstruction 56. This designshown in FIG. 6 is therefore of considerable benefit.

FIG. 7 corresponds to FIG. 6 and/or 4 and illustrates a quarter cutawayof the gland plate assembly 50. It will be noted that portions of thegland plate assembly are hollow 57.

Said hollow portions 57 correspond to areas where the strength of thegland plate assembly 50 is deemed not to be critical. Should any regionof the gland plate assembly 50, other than the bolt slot area 58,require strength or rigidity, then one or more protrusions,indentations, or portions of displaced material could be incorporatedadjacent to said region.

Referring back to FIG. 2 the sleeve 18 is preferably a component whichmay be pressed from sheet steel. While the invention is by no meanslimited to this, this is a preferred production process in order tomaintain a low assembled seal cost price.

FIG. 8 of the accompanying drawings illustrates an alternative sleeve 60and sleeve elastomeric member 61.

FIG. 9 illustrates a single component seal of the invention. The .glandplate assembly 70 is of similar shape to the aforementioned figures.However the seal design is a component design rather than a cartridgedesign which incorporates a sleeve member. This design in FIG. 9 hasfewer components than that of the cartridge seal variant and thereforewill be a produced at a lower cost price.

The seal of FIG. 9 includes a pump setting component 71 which axiallypositions the rotary seal face assembly 72 in terms of the correctspring 73 working length.

FIG. 10 shows a double seal 100 version of the invention. Once again therotary and axially floating seal face 101 is spring biased towards astatic stationary seal face 102. The rotary seal face 101 is allowed toslide on the static seal face 102. The interface between the rotary sealface 101 and stationary seal face 102 forms a sealing area 103. Thissealing area 103 is the primary seal that prevents the process media 104from escaping from the process chamber 105. The other secondary inboardsealing points remain identical in concept to FIG. 2.

Towards the outboard side of the seal, the outboard rotary and axiallyfloating seal face 118 is spring biased towards a static stationary sealface 119. The rotary seal face 118 is allowed to slide on the staticseal face 119. The interface between the rotary seal face 118 andstationary seal face 119 forms sealing area 120. This outboard sealingarea 120 is the primary seal that prevents the barrier media 121 fromescaping from the barrier chamber 114. The barrier media 121 is alsosealed at the inboard side of the assembly, by sealing area 103.

At the outboard side, the secondary sealing areas include elastomericmember 117 and elastomers 137 and 138.

Once again the static outboard seal face 119 is prevented from rotatingby the frictional drive of elastomeric member 117 against gland 122. Thegland could incorporate an alternate anti-rotation drive mechanism suchas a pressed lug, or a pin and slot arrangement.

An intermediate component 123 is positioned between the two stationaryseal faces 102 and 119. Said intermediate component 123 is preferablymanufactured from a press steel plate of thin thickness. In analternative embodiment, this intermediate component 123 is a machineditem.

The gland plate assembly 124 is manufactured from three, pressed,preferably sheet steel, components. This assembly 124 is designed insuch a way as to eliminate or limit subsequent conventional machiningoperations. FIG. 10 therefore illustrates that the invention is notlimited to a particular number of pressed sheet steel components whichmake up the gland plate assembly. Sufficiently to state one or morepressed steel components are positioned in such a way to provide thegland plate assembly with strength at a low manufacturing cost.

Barrier media 121 enters insertion hole 125. Preferably a correspondinginsertion hole is punched through the gland plate assembly 124 andsealed by rubber washers 127 and 128, if necessary, at either side ofthe insertion hole 126.

Barrier media 121 enters the barrier chamber 114 preferably via aplastic tube 129 inserted through a rubber washer 127 and 128 andfitting 130 arrangement. This provides a pressure tight and leak tight,leak tight joint. Said barrier fluid 121 lubricates and cools seal faces120 and 103 and is evacuated via a similar hole and tube arrangementpositioned at another place in the gland plate assembly 124.

Thus, it can be seen that pipe 129 and fitting assembly 130 have beenincorporated into the hollow cavity 131 of the gland plate assembly 124.

Fittings 130 are preferably of “panel” type construction which are idealfor creating a pressure tight, leak free seal in a thin sheet metalconstruction such as the gland plate assembly 124.

Panel fittings 130 and 132 are fitted to the punched holes 126 and 133.A pipe 129 connects said fittings, 130 and 132 providing a pressuretight joint. Pipe 129 is preferably a plastic tube. Fittings 130 and 132preferably accommodate said plastic pipe 129 with a “push-fit”, leaktight seal. The invention is not limited to the use of this pipe 129 andfitting 130 and 132 construction. However such a construction is aparticular low cost option.

The fitting and pipe assembly 134 is typically installed prior toassembling the rear gland plate flange 135 to the front gland plateflange 136. The front gland plate 136 has an opening, which correspond,to the fitting position in the rear gland plate 135, thereby allowingthe joining of both flanges which create the gland plate assembly 124.

FIG. 11 illustrates a double component seal of the invention. The glandplate assembly 140 is of similar shape to the aforementioned figures.However the seal design is a component design rather than a cartridgedesign which incorporates a sleeve member.

Gland plates of the invention may be employed for both rotary seals andstationary seals, single, double or triple mechanical seals, whetherdesigned in a cartridge or component seal format.

Furthermore, the design could be used for both pressurised andnon-pressurised barrier fluid systems.

The invention may be used with metallic components as well asnon-metallic components such as plastic. Some types of equipment rotatethe housing and have a stationary shaft. It is considered that theinvention can be similarly applied to such designs.

FIG. 12 illustrates that, the gland plate assembly 150 of the inventionis by no means limited for the use of a mechanical seal. Rotatingequipment is often sealed by other means such as packing 151.

Packing is a traditional manner of sealing rotating equipment at a lowcost The gland plate assembly 150 of the invention is thereforeparticularly suited for this type of sealing since this too is a lowcost option.

As shown in FIG. 12, the gland plate assembly 150 can be adopted totransmit the compressive forces from at least one screw 152 to thepacking 151. This thereby creates a seal between the stationary processchamber 153 and rotating shaft 154.

In summary, the invention provides a gland plate assembly whichcomprises one or more components manufactured from a relatively thinmaterial, said material formed into a shape which is sufficiently rigidto hold a stationary member which may subsequently slide relative to acorresponding rotary member or may be, for instance, a packaging memberwhich creates a seal between a stationary member and a rotating member.In general, no subsequent machining operations are required after thegland plate forming operation. The assembly may be of modularconstruction thereby permitting its use in more than one sealingarrangement.

The components of the gland plate assembly may be mechanically, and/orchemically, and/or thermally connected together in a non-detachablemethod. The components of the gland plate assembly are located relativeto one another by at least one location member, said location memberbeing an integral part of at least one of the former components.Alternatively, the location member is a separate part to any of theformer components.

A gland plate assembly of the invention may contain at least onefitting, which connects two regions of the mechanical seal, allowing afluid to be passed between the two regions The fitting, including aconnecting pipe, may be positioned in the hollow cavity created by atleast two components which comprise the gland plate assembly.

1. A gland plate comprising a rigid, disk-shaped element comprising atleast one radially extending wall having a thickness of from about 0.1to 4 mm.
 2. A gland plate according to claim 1 wherein said elementcomprises two axially spaced, radially extending walls.
 3. A gland plateaccording to claim 2 wherein said element further comprises inner andouter circumferential walls extending between said radially extendingwalls.
 4. A gland plate according to claim 3 wherein said element is ahollow structure.
 5. A gland plate according to claim 3 wherein saidelement is filled with concrete, plastics or water.
 6. A gland plateaccording to claim 1 wherein said at least one wall is made of metal. 7.A gland plate according to claim 6 wherein said at least one wall isformed by a pressing operation.
 8. A gland plate according to claim 1,further comprising: a first part providing a first radially extendingwall and a second part providing a second radially extending wall, saidfirst radially extending wall being axially spaced from said secondradially extending wall.
 9. A gland plate according to claim 8 whereinsaid first and second parts together provide inner and outercircumferential walls.
 10. A gland plate according to claim 1 whereinthe gland plate is provided with one or more through holes.
 11. A glandplate according to claim 10 wherein each of said through holes is formedby a pressing or punching operation.
 12. A gland plate according toclaim 11 wherein material displaced when each of said holes is beingformed provides a strengthening support around said hole.
 13. A glandplate according to claim 1, wherein the gland plate comprises a hollowstructure having first and second radially extending walls, and furthercomprising: means for feeding fluid through said gland plate.
 14. Asealing arrangement, comprising: a gland plate comprising a rigid,disk-shaped element comprising at least one radially extending wallhaving a thickness of from about 0.1 to 4 mm.
 15. A mechanical seal,comprising: a gland plate comprising a rigid, disk-shaped elementcomprising at least one radially extending wall having a thickness offrom about 0.1 to 4 mm.